In the disclosure of the present invention reference is mostly made to the treatment of diabetes by injection or infusion of insulin, however, this is only an exemplary use of the present invention.
Those people who have “type 1 diabetes,” also called insulin-dependent diabetes mellitus (IDDM), do not produce insulin and need regular injections or infusions of insulin to maintain their blood glucose at a normal level. As a result, people with type 1 diabetes must test their blood sugar regularly, often several times a day, to determine the amount of insulin to be injected or infused. Devices for testing glucose levels in blood are known in the art and may typically comprise a glucose sensor adapted to receive a test strip with a blood sample, the sensor being arranged inside a housing behind a strip port through which the strip can be inserted into the sensor, see e.g. U.S. Pat. No. 5,597,532, which is hereby incorporated by reference in its entirety. Many other electrochemical and colorimetric test devices are known in the art. In general such a device is termed a blood glucose meter or BGM for short.
A BGM will typically be a pocket-sized portable device adapted to be carried by the diabetic user and will thus be battery operated. The batteries (or more correctly: electric cell(s)) may be disposable or rechargeable. In the latter case the BGM normally has an electrical power inlet connector allowing the rechargeable batteries to be charged in the BGM, either by connecting the BGM to a charger via a cable or by placing it in a charging cradle, the charger or cradle being connected to a utility power outlet. Examples of charging arrangements for BGM devices are shown in e.g. US 2002/0060247, US 2004/016746, US 2006/0261781 and EP 1 494 124 which are hereby incorporated by reference.
If the BGM, for any purpose, can be connected to an external device by an electrical connection, special care must be taken to minimise the possible leakage current through to the BGM and ultimately the user. With a built in blood glucose strip port, the patient may be in galvanic contact with the medical device through the strip when the blood is applied and if the medical device simultaneously is connected to an external system (e.g. a PC for the exchange of data or a wall plug charger) the possible leakage current might be too high. To prevent this is possible to reduce the leakage current by galvanic isolation of the strip sensor unit from the rest of the system. Further, it may be possible to use special medical-grade chargers or other peripheral equipment which has been adapted to minimize the risk of supplying a high voltage or current to an absolute minimum.
Having regard to the above, it is the object of the present invention to provide a device for the testing of body fluids which can be connected electrically to an external device or system, which is safe in use and which can be manufactured in a cost-effective manner. It is a further object of the invention to provide such a device which is easy to use and operate and which protects against incorrect use.